<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>自适应布局</title>
<style>
	*{ margin:0; padding:0; font-size:40px; color:white; }
	#top{ width:100%; height:50px; background:red; }
	#content{ width:100%; height:100px; background:red; 
		margin-top:20px; }
</style>
</head>
<body>
	<div id="top">头部</div>
    <div id="content">内容</div>
</body>
</html>
